This application is based on Japanese Patent Application No. 10-154640, filed Jun. 3, 1998, and on Japanese Patent Application No. 10-154631, filed Jun. 3, 1998, the contents of which are incorporated herein by reference.
The present invention relates to a computer system and lock control method and, more particularly, to a computer system for connecting a network using an expansion unit with a built-in network controller, and a lock control method for locking/unlocking the computer system to/from the expansion unit.
In recent years, various kinds of notebook type personal computers (note PCs) that are easy to carry and can be battery-driven have been developed. Such note PC can be attached on an expansion unit called a docking station or docking base, as needed, so as to expand its functions.
Normally, the expansion unit has a lock mechanism for locking the note PC to the expansion unit to inhibit the former from being detached from the latter. The conventional lock mechanism works when the note PC is attached on the expansion unit, and cannot unlock the note PC unless undocking is done in a predetermined procedure, e.g., by password input, special operation using a key, or the like. For this reason, once the note PC is attached on the expansion unit and begins to be used, it cannot be detached from the expansion unit unless undocking is done in a predetermined procedure, e.g., by password input, special operation using a key, or the like. Hence, the degree of freedom in attachment/detachment and portability of the note PC are considerably impaired.
Recently, IBM Japan has released desktop PCs having functions called xe2x80x9cWake_on_LAN (WOL)xe2x80x9d for turning on desktop PCs under the remote control from a server, and xe2x80x9cAlert_on_LAN (AOL)xe2x80x9d for automatically informing the server of abnormality of each desktop PC.
In case of a note PC, it is preferable that a LAN controller be accommodated not in the PC main body but in an expansion unit called a docking station or docking base, and that expansion unit be permanently connected to a LAN in an office. In this way, when the note PC is docked with the expansion unit in the office, it can be used as a desktop PC. On the other hand, when the user leaves the office, he or she can detach the note PC from the expansion unit and can carry it.
However, in such note PC which comprises a LAN controller with the AOL/WOL function on the expansion unit side, even when the note PC is attached on the expansion unit, the LAN controller is often not used by the note PC in practice.
More specifically, since the AOL/WOL function is implemented based on TCP/IP, an IP address is used for specifying each PC. In case of the not e PC which has the LAN controller on the expansion unit side, since the IP address is stored in the expansion unit side, the combination of the note PC and expansion unit is fixed to use the AOL/WOL function, and if that combination is not satisfied, the note PC must be inhibited from using the LAN controller. When the AOL/WOL function is used, even when the power switch of the note PC is turned off, the LAN controller must be kept ON for the AOL/WOL function.
Hence, when the aforementioned lock mechanism is directly used, once the note PC is connected to the expansion unit, even when the LAN controller is inhibited from being used, the note PC cannot be detached from the expansion unit unless undocking is done in a predetermined procedure, e.g., by password input, special operation using a key, or the like. On the other hand, when the power supply of the PC is turned off, and the LAN controller can no longer be used from the note PC, the note PC cannot be detached from the expansion unit unless undocking is done in a predetermined procedure.
To achieve multi-functions in a system arrangement using this expansion unit, a required function module is to be arbitrarily continuously operative as needed independently of the power ON/OFF state of the docked (attached) computer main body or even when the computer main body is undocked (detached). However, a conventional system of this type cannot implement a function that can meet such requirement.
In either system arrangement, when the computer main body (PC main body) is detached (undocked) from the expansion unit, the operation power (INT-PS) cannot be supplied to the internal circuits of the expansion unit. Also, when the power supply of the computer main body attached (docked) on the expansion unit is OFF, the operation power cannot be supplied to the internal circuits. Hence, the conventional system using the expansion units cannot realize a network system with the above-mentioned wake-up and alert functions.
It is an object of the present invention to provide a computer system and lock control method, which can dynamically control the locked/unlocked state of a lock mechanism in accordance with the state of a LAN controller, and can implement lock control with a high degree of freedom in attachment/detachment while maintaining sufficiently high operation reliability.
It is another object of the present invention to provide a computer system using an expansion unit, which can continuously operate an arbitrary function module in the expansion unit as needed independently of the power ON/OFF state of a computer main body attached on the expansion unit or even when the computer main body is detached from the expansion unit, thereby easily realizing a network system with wake-up and alert functions on the system using the expansion unit.
In order to achieve the above objects, according to the present invention, a computer system removably docking with an expansion unit, comprises: state detecting means for detecting whether or not the use of the expansion unit by the computer system is in an enable state; and lock control means for locking, during the enable state of the use of the expansion unit, the computer system in the expansion unit in order to inhibit the computer system from being removed from the expansion unit.
In this computer system, the lock/unlock state of a lock mechanism is dynamically controlled depending on whether or not the use of the expansion unit by the computer system is possible. While the expansion unit can be used by the computer system attached on that expansion unit, the computer system main body is locked to the expansion unit and is inhibited from being detached therefrom, since accidental detachment may lead to operation errors. While the expansion unit cannot be used by the computer system, the computer system main body is unlocked, and can be detached without requiring any special operation. Hence, lock control with a high degree of freedom in attachment/detachment can be attained while maintaining sufficiently high operation reliability.
The state detecting means is characterized by including docking condition detecting means for detecting whether or not the computer system docked with the expansion unit satisfies a predetermined docking condition for using the expansion unit, and the computer system is locked in the expansion unit while the computer system is in an operative state and the docking condition is satisfied.
With this arrangement, only when the docking condition is satisfied and the computer system is operative, the computer system main body is locked to the expansion unit. When the power supply of the computer system is turned off in this state, the computer system main body is unlocked, and can be immediately detached from the expansion unit.
According to a second aspect of the present invention, a lock control method for use in a computer system removably docked to an expansion unit, comprises the steps of: detecting whether or not the use of the expansion unit by the computer system is in an enable state; and locking, during the enable state of the use of the expansion unit, the computer system in the from being removed from the expansion unit.
According to a third aspect of the present invention, an expansion unit to which a computer system is removably dockable, comprises: a lock mechanism for locking, in the expansion unit, the computer system docked to the expansion unit; and means for receiving a first control signal for powering on and off the expansion unit in cooperation with the transition of the computer system docked to the expansion unit into an operative state, a stop state, and a sleep state, and controlling lock/unlock operation of the lock mechanism in accordance with the first control signal.
Since the network control unit has a plurality of states determined depending on the combinations of the ON/OFF state of a switch that connects/disconnects the bus of the computer system to/from the network control unit, and the power supply state to the network control unit, it preferably manages these states to control locking/unlocking in cooperation with the state of the network control unit.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.